Removable dental bridge attachment.



F. H. SKINNER.

REMOVABLE DENTAL BRIDGE ATTACHMENT.

APPLICATION I FILED JAN. 2, I914.

1,140,539., Patented May 25, 1915.

THE NORRIS PETERS C0,, PHDYC-LITHOI. WASHINGTON D. C.

FRANK- I-I. SKINNER, OF CHICAGO, ILLINOIS.

REMOVABLE DENTAL BRIDGE ATTACHMENT.

. Specification of Letters Patent.

Patented May 25, 1915.

Application filed January 2, 1914. Serial No. 809,850.

, To all whom it may concern:

Be it known that I, FRANK H, SKINNER, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Removable Dental BridgeAttachments, of which the following is a specification.

This invention relates to improvements in dentistry, and has referencemore particularly to a new and improved device for removably attachingbridge-work to natural teeth abutments.

The invention relates to that type of bridge attachment which employs anabutment member permanently secured to the root of a natural tooth andcarrying a spring post which frictionally engages a socket in the bodymember of an artificial crown on a bridge to removably secure the latterin place on the abutment member. Heretofore, so far as I am aware, suchpost 'has been formed as an integral part of the abutment member, or hasbeen soldered or.

otherwise permanently mounted on the abutment member. These posts notinfrequently break or, in time, lose a measure of their holding power,and consequently have to be replaced, thereby necessitating the removalof the entire abutment member from the root of a natural tooth,involving discomfort to the patient and the expenditure of considerabletime and labor on the part of the dentist.

The object of the present invention is to improve upon this constructionin such a manner as will make it wholly unnecessary to remove theabutment member from the root when a post has to be repaired or renewed.

The invention is illustrated in the accompanying drawing, in whichFigure 1 is a top plan view of a lower jaw showing a dental bridgeembodying my invention applied thereto. Fig. 2 is a view of the same jawomitting the bridge. Fig. 3 is an enlarged cross section on the line 3-3of Fig. 1. Fig. 4 is an enlarged cross section on the line H of Fig. 1.Fig. 5 is an elevation, partly in vertical section, on a furtherenlarged scale, of my improved attaching device. Fig. 6 is an end viewof the split post.

Referring to the drawing, 5 designates the gum of a lower jaw, and 6 agroup of natural teeth therein.

7 designates the root of a bicuspid, and 7 the root of a molar, to aplurality of which roots located on opposite sides of the jaw thebridge, designated as an entirety by 8, is attached. These roots are cutoff substantially flush with the edge of the gum, and 9 designates anabutment member that is fitted to the exposed end of the root 7 andcarries a pin or post 10 that is cemented within the canal of the toothas usual.

Integral with or soldered to the abutment member 7 is an internallythreaded boss 11. 12 designates the post which, as best shown in Figs. 5and 6, is split longitudinally through the major portion of its length,as

bridge-plate 8 at locations registering with the split posts mountedupon the roots as described are metal socket members 16 that are of asize such as to have a snug sliding fit with the posts 12, there beingsufficient friction due to the said fit to hold the bridge securely inplace under service conditions;

the spring prongs of the posts being slightly compressed by the socketmembers upon the application of the bridge to the jaw, but permittingthe ready removal of the bridge upon the application of suflicient forceto withdraw the socket members from the split posts.

Fig. 3 illustrates a preferred form of the bridge abutment or crown whenapplied to a multiple-prong root. In this case, the abutment plate orcap 9 is provided with a pair of spaced pins or posts 10 which enter thecanals of the two prongs of the root. In such a case, and especiallywhere there is a short bite, the length or height of the integral postmay be reduced, relatively to the height of that shown in Fig. 4, byextending the internally threaded boss 11 through the abutment plate orcap 9' and into the upper end of the root whereby the upper end of thethreaded boss 11' may be brought substantially flush withthe outersurface of the abutment cap 9, and the split post 12 is screwed thereinin the manner already described.

In the application of the invention, the anchor roots,ha ving beensuitably prepared, the abutment members with their root pins, andcarrying their internally threaded bosses, are permanently securedthereto by cementing in the usual and known manner. The shank of thepost is then threaded into the boss. Finally, the. bridgeplate, havingthe metal socket members 16 embedded therein, is forced down over thesplit posts and securely held upon the latter and against the abutmentmembers by the frictional grip of the posts within their respectivesocket members. By the application of suificient force the bridge canreadily be removed from the posts forcleaning, repair or other purposes.

Prior to my present invention, bridge-anchoring posts of the generalnature and character described have been made solid, have beenpermanently soldered or otherwise secured to the root abutment orcrown,"

and the posts on opposite sides of the jaw have been inclined or slantedslightly inwardly or toward each other, In such cases the holding orgripping efiect upon the bridge-plate has been secured as a result ofspringing the posts outwardly slightly during the application of thebridge. Ihis produces a lateral strain upon the natural roots of theteeth which is undesirable and not infrequently results in producingunhealthy and diseased conditions, or else loosens the abutment crowns.My invention improves these conditions in several respects. In thefirstplace, the posts can be, and preferably are, set vertical, thusavoiding any side strain during the application and removal of thebridge; and the vertical splitting of the posts, combined with snuglyfitting socket members, produces an ample frictional holding efiect. Inthe second place, the individual posts being readily removable byasimple unscrewing operation, my improvement entirely dispenses with thenecessity of removing the:

entire abutment member or crown from the root when the post happens tobreak or otherwise becomes detective through loss of its resiliency andholding power, thus mak ing the operation of renewing the post a an esaid parts, a root pin onthe inner side of said abutment plate adaptedto be. cemented in the canal of the root, and a socketed bridge-platefrictionally engaging said springpost. r V

2, In a removable dental bridge attachment, the combination with anabutment plate having on one side. thereof a. pin adapted to be cementedin the'canal of a natural. root and on the opposite side an internallythreaded boss, of a longitudinally split spring post. having a threadedshank of reduced diameter engaging said boss,- and a socketed bridgeplate frictionally engaging said spring post. 7 V.

FRANK H'. Witnesses: r

VVSAMUEL N.; POND,

MARY M. LErPo.

Copies of this patent may be. obtained for five cents each, byaddressing the Commissioner of gatents, Washington, 1). G.

